Nutritional supplements for age-related macular degeneration

Age-related macular degeneration (AMD) is a condition which mainly occurs in older people. In AMD the cells of your macula, the central part of the retina at the back of your eye, stop working. This can cause deterioration in your central vision. This is the sight we use for detailed tasks such as reading and recognising faces.

Two type of AMD

There are two types of AMD, "dry" and "wet". In the dry type, the cells at your macula slowly stop working correctly. In the wet type, the cells stop working and your eye tries to fix this problem by growing new blood vessels. However, these new vessels are weak and grow incorrectly. They then leak, causing damage and scarring at your macula.

Wet AMD is the quicker progressing form of the condition, leading to serious changes to your central vision in a short period of time. There is currently no treatment for dry AMD, but there are treatments available for wet AMD. However, anything which may prevent the progression of dry to wet AMD is helpful in delaying sight loss.

Antioxidants for AMD

The nutritional supplements concerned with AMD are the antioxidant vitamins A (which our bodies convert from beta-carotene in our diets), C and E, as well as the trace element zinc and the micronutrients lutein and zeaxanthin. Lutein and zeaxanthin are not made within the body and can only be obtained from what we eat. In most people, they naturally collect at the macula.

It is thought that antioxidants are helpful in AMD because of the "free radical" theory of cell damage. This means that over your lifetime, free radicals, highly reactive substances created in your body by breathing, eating and by other factors such as air pollution and smoking tobacco, cause damage to the cells in your body. This is the "wear and tear" we call ageing.

Antioxidants are thought to help by "mopping up" these free radicals, to delay or prevent them from damaging your cells. Research into supplements for AMD has looked at whether or not antioxidants can help to protect the macula from these age-related changes.

Can diet or supplements prevent AMD?

It is possible to have visible changes at the retina, which an optician or ophthalmologist (eye specialist) can see on examination, and not have any problems with your vision.

An optician or ophthalmologist may see "drusen" when they examine your retina. Drusen are small deposits under the retina which can be seen as yellow dots. Having small numbers of drusen is not the same as having AMD. Many people have some small drusen as a natural part of ageing without being diagnosed with AMD.

Someone may be told they have early AMD if they have larger drusen in one or both eyes. However, people with early AMD may also not have any problems with their vision.

Several studies have looked at the role of antioxidant supplements in the prevention and progression of AMD. At present there is no evidence that people who do not have AMD should take lutein/zeaxanthin, antioxidant supplements or multivitamins marketed for eye health to prevent their developing AMD in the future.

It is generally thought that a healthy diet full of fruit and vegetables as well as regular eye tests to monitor drusen can help to keep your eyes as healthy as possible. However, there is no firm evidence as yet linking specific foods or diets to the prevention of AMD.

The Age Related Eye Disease Study (AREDS)

AREDS was a large-scale clinical trial carried out in the United States that followed about 3,600 people who were already diagnosed with AMD at different stages of severity, including many people with early AMD.

The aim of AREDS was to find out whether nutritional supplementation could help slow down the development of AMD. People on the trial were given high levels of antioxidants and zinc to see what effect this would have on their progression to advanced AMD.

Advanced AMD is where someone has new blood vessel growth at the retina (wet AMD) or "geographic atrophy" where a large part of the central retina is no longer working due to dry AMD. People with advanced AMD are likely to have changes in their central vision.

Results of AREDS

AREDS found that people diagnosed with early AMD and who took the "AREDS formula" used on the trial, were 25-30 per cent less likely to go on to develop advanced AMD. They also reduced their risk of developing central vision loss by 19 per cent.

The AREDS formula which gave these results, taken every day was:

500 milligrams (mg) of vitamin C

400 international units of vitamin E

15mg beta-carotene

80mg zinc as zinc oxide

2mg copper as cupric oxide (added because high levels of zinc can reduce the amount of copper in the body).

AREDS2

While the AREDS trial was being carried out, theories that lutein, zeaxanthin and omega-3 fatty acids were helpful in slowing down the progression of AMD were also being put forward. Until recently there wasn’t much evidence available as to whether or not these were beneficial to take in relation to AMD, so a second trial, AREDS2 was carried out to explore this.

Results of AREDS2

AREDS2 found that when lutein and zeaxanthin replaced beta-carotene in the original AREDS formula, the risk of someone going on to develop advanced AMD decreased by a further 10 per cent. For people on the trial who had a poor dietary intake of lutein and zeaxanthin this increased to 20 per cent.

The study also looked at adding in omega-3 fatty acids to see if this made a difference. AREDS2 found that adding omega-3 fatty acids did not decrease someone's risk of going on to develop advanced AMD and so did not include this in the new formula.

Studies have shown that beta-carotene may increase the risk lung cancer in smokers, or in people who had quit smoking for a year or less. In AREDS2 it was found that there was still a risk of lung cancer in ex-smokers who had stopped smoking more than a year before starting the trial. Therefore, it was recommended that beta-carotene should be removed from the original AREDS formula and it is now possible to buy AREDS-type formula supplements which have no beta-carotene in them. No link was found between lung cancer and lutein and zeaxanthin for either current or ex-smokers.

The study also looked at reducing zinc, because of the potential health risks of taking large quantities of zinc. However, it was not found that changing the amount of zinc brought about any problems or improvements for people on the trial and therefore this was not changed. However, some doctors may recommend avoiding high levels of zinc and lowering the amount of zinc will not affect how well the supplement works.

Should I take a supplement for AMD?

Based on the results of AREDS and AREDS2, the current recommended daily formula to slow down the progression of AMD in people already diagnosed is:

500 milligrams (mg) of vitamin C

400 international units (equivalent to about 270mg) of vitamin E

10mg lutein

2mg zeaxanthin

25mg or 80mg zinc as zinc oxide (as recommended by your doctor)

2mg copper as cupric oxide.

The AREDS and AREDS2 studies both involved large numbers of people and were carried out over several of years. The evidence from these studies that taking the formula does help to reduce the risk of going on to develop advanced AMD for people already diagnosed with early AMD is therefore very positive. However, at the moment there is no other research to compare these results to, and so this is the only information that we currently have to go on with regards to nutrition and AMD.

If you are considering taking the formula recommended by the AREDS2 trial, you may want to discuss this with your optician or ophthalmologist first. They should be able to give an idea of what stage your AMD is at and whether or not taking the supplement is a good idea in your situation.

If you are thinking about taking a supplement for AMD it would also be important to discuss this with your GP, as taking larger amounts of vitamins and minerals than those found in an everyday diet may not be suitable for you.

Although the results of both the AREDS trials are encouraging news, it currently cannot be said that these supplements will help everyone who is diagnosed with early AMD. This means that generally speaking the NHS does not fund these supplements. However, this can depend on where you live and your GP would be able to advise you about what the funding situation is in your area.

Eating a balanced diet with plenty of fruits and vegetables is a good way to keep yourself healthy and it may be helping your eyes. Supplements can also be useful if you have difficulty with this type of diet, for example if you have problems with your digestion. If you have any concerns about your diet or feel that it might be helpful to take a supplement for AMD you may want to start by discussing this further with your GP.

Coping

Being diagnosed with an eye condition can be very upsetting. You may find that you are worried about the future and how you will manage with a change in your vision. All these feelings are natural.

Some people may want to talk over some of these feelings with someone outside their circle of friends or family. RNIB can help, with our Helpline and our Sight Loss Counselling team.

Your GP or social worker may also be able to help you find a counsellor if you think this would help you.

Sometimes it can help to talk about your feelings or share your experience with people who may have had similar experiences.

Help to see things better

Ask your ophthalmologist, optometrist or GP about low vision aids, like a magnifier, and ask for a referral to your local low vision service. You should also ask whether you are eligible to register as sight impaired (partially sighted) or severely sight impaired (blind). Registration can act as your passport to expert help and sometimes to financial concessions. Even if you aren’t registered a lot of this support is still available to you.

Local social services should also be able to offer you information on staying safe in your home and getting out and about safely. They should also be able to offer you some practical mobility training to give you more confidence when you are out.

Low Vision Services can help people make the most of their sight. They:

are normally located within the hospital eye departments

are usually accessed through a referral from the hospital eye consultant or your GP

offer a thorough assessment of vision and prescribe the appropriate magnifier for the individual

provide training on how to best use the magnifier

give advice on lighting which can be important in getting the most benefit out of the magnifiers

give advice on maximising the use of peripheral vision.

Our Helpline can also give you information about the low vision services available, and our website offers lots of practical information about adapting to changes in your vision and products that make everyday tasks easier.

Further support

The RNIB Helpline is your direct line to the support, advice and products you need. We'll help you to find out what's available in your area and beyond, both from RNIB and other organisations.